Editing Radioactive decay (section)

=== Electron capture ===
{{Main|Electron capture}}
In electron capture, some proton-rich nuclides were found to capture their own atomic electrons instead of emitting positrons, and subsequently, these nuclides emit only a neutrino and a gamma ray from the excited nucleus (and often also [[Auger electron]]s and [[characteristic X-ray]]s, as a result of the re-ordering of electrons to fill the place of the missing captured electron). These types of decay involve the nuclear capture of electrons or emission of electrons or positrons, and thus acts to move a nucleus toward the ratio of neutrons to protons that has the least energy for a given total number of [[nucleon]]s. This consequently produces a more stable (lower energy) nucleus.

A hypothetical process of positron capture, analogous to electron capture, is theoretically possible in antimatter atoms, but has not been observed, as complex antimatter atoms beyond [[antihelium]] are not experimentally available.<ref>{{Cite web |title=Radioactive Decay |url=http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch23/modes.php#fission |access-date=2022-05-05 |website=chemed.chem.purdue.edu}}</ref> Such a decay would require antimatter atoms at least as complex as [[beryllium-7]], which is the lightest known isotope of normal matter to undergo decay by electron capture.<ref>{{Cite web |title=CH103 – Chapter 3: Radioactivity and Nuclear Chemistry – Chemistry |url=https://wou.edu/chemistry/courses/online-chemistry-textbooks/ch103-allied-health-chemistry/ch103-chapter-3-radioactivity/ |access-date=2022-07-05 |language=en-US}}</ref>